The invention is in the field of security alarms for entryways and windows and involves a device and technique for using it that is primarily in the realm of the workman/installer.
Burglar alarms typically include long circuits with interruptible switches wired in series, placed at doors and windows throughout the building such that opening any one of them opens the circuit and triggers the alarm. Each entryway of a residence or business building, such as a window, door, or chimney, has at least one the these interruptible elements so that every possible entryway into the building is wired.
Sensor switches on sliding glass doors and windows typically comprise magnetic reed switches. A dowel-shaped switch housing is inserted into a hole drilled up into the top of the casing from underneath so that it is spaced just above the top of the underlying door as the door slides. The switch is installed in the least inaccessible location in the overhead sliding door casing, and then the trip magnet is installed on the top of the door. The magnet is positioned to align with the switch when the door is closed, so that it holds the reed of the magnetic switch in the closed position. Rupture of the line, or the opening of any of the fixtures to which a switch is mounted, interrupts the circuit and actuates the alarm.
Traditionally, the installation of the magnetic trigger on the top of the sliding door has not been a problem because the doors could be slipped off of the their tracks from the outside very easily, and the magnet could be glued to the top of the door between the peripheral sidewalls. It was simple, rugged, inexpensive and straightforward.
This has all changed recently since sliding door designs have been changed to thwart trespassers. Manufactures now making doors that cannot be removed from the outside. The design is so effective that now, what used to be the simple procedure of gluing a magnet on the top of a door, has become a time-consuming project. What used to take several minutes now takes two hours or more. The door has to be dismantled completely, and the glass removed from the frame to provide access to the top of the door beneath the overhead casing. The alternative is put a side-mounted magnet on the door, which is not as attractive and alerts the burglar to the location of the warning device.
Related to the problem of the sliding door that cannot be removed from its tracks is the fact that there are still in existence many of the older door types which can still be removed from their tracks, so that any trip that would work especially well for the new doors but not for the old doors would require a double parts inventory.
There is a need for a system and device for installing a magnet in a modern sliding door which does not require dismantling and reassembly of the door.